The present invention relates to extension arm devices and components therefor. More particularly, the present invention relates to extension arm devices and components therefore having enhanced reinforcement and improved designs.
In the past, people have placed video monitors and other electronic equipment on desks, tabletops, or upon other equipment such as personal computers or workstations. One drawback to these configurations is the reduction in available workspace taken up by the equipment. Another drawback is the inability to place the equipment in a desired location. A further drawback is the potential for eye strain, neck strain and/or a cumulative trauma disorder such as carpel tunnel syndrome from non-ergonomic placement of devices such as monitors and keyboards.
Different products have been provided in order to overcome these obstacles. For example, in one solution, a monitor stand or printer stand elevates the apparatus over other equipment on a desk. While this may free up workspace, it often places the equipment in an undesirable location. Another solution employs a mechanical extension arm to support the monitor. Extension arms free up workspace and allow users to place the equipment where it is wanted. Various extension arm devices are shown and described in U.S. Pat. No. 6,478,274, entitled “Arm Apparatus for Mounting Electronic Devices,” and in U.S. Pat. Nos. 6,409,134, 6,609,691, 6,619,606, entitled “Arm Apparatus For Mounting Electronic Devices With Cable Management System,” all of which are fully incorporated by reference herein.
FIGS. 1-7 illustrate a known extension arm 10 for mounting an electronic device. As shown in FIG. 1, the main elements of the extension arm 10 are a first endcap 12, an upper channel 14, a lower channel 16, a second endcap 18, and a forearm extension 20. The first endcap 12 has an endcap shaft 22 that is pivotably attachable to a rigid support mount (not shown), such as an orifice sized to accept the endcap shaft 22 or a track configured and sized to engage the grooves on endcap shaft 22. The first endcap 12 is pivotably coupled via pins 24 to both the upper channel 14 and the lower channel 16. The opposite ends of the upper channel 14 and the lower channel 16 are pivotably coupled via pins 24 to the second endcap 18. The forearm extension 20 is pivotably coupled to the second endcap by the endcap shaft 22, which may be a hollow tubular member fixedly attached to the second endcap 18. The forearm extension 20 has a vertically disposed hole 26 therethrough for accepting a shaft 90 of a mounting device (not shown) such as a tilter, platform or other apparatus. The forearm extension 20 includes a hollow interior 92 so that a cable 94 of the mounted device can pass through the forearm extension 20. The cable 94 can extend through hollow tubular member of the second endcap 18. The cable 94 can pass through a sheath or cover 96 attached to the lower channel 16. The hollow interior 92 and/or the sheath 96 hide the cable 94 from view.
The combination of the upper and the lower channels 14, 16 and the first and the second endcaps 12, 18 form an adjustable parallelogram that permits a device coupled to the forearm extension 20 to be raised and lowered to a desirable height. The parallelogram retains its position by employing an extension/retraction means such as a gas spring 28, which is pivotably and adjustably attached to the first endcap 12 and the upper channel 14, as will be further described below. Generally, the gas spring 28, e.g., a gas type hydraulic cylinder and a retractable piston rod, is sized so as to have a fixed length until an upward or downward force is exerted at the second endcap 18 that exceeds the gas spring's designed resistance. Thus, the gas spring 28 causes the parallelogram to retain its position when the only force exerted at the second endcap 18 is the weight of the device, but permits the parallelogram to be adjusted when a user pushes the device coupled to the forearm extension 20 up or down.
FIG. 2 illustrates a side view of the first endcap 12, having the endcap shaft 22 disposed on a first end 30 of the first endcap 12. To provide a rigid connection between the two pieces, the endcap shaft 22 is typically machined from steel and is inserted into the first end 30 during the casting process of the first endcap 12. The endcap shaft 22 has a hole 32 formed in an end of the endcap shaft 22 that is inserted into the first endcap 12. The first endcap 12 is typically fabricated from cast aluminum. The first endcap 12 also has a second end 34 having a hole 36 disposed therethrough. Disposed within the first endcap 12 is a threaded rod 38. A first end 40 of the threaded rod 38 is inserted into the hole 32 at the base of the endcap shaft 22. A second end 42 of the threaded rod 38 is aligned with the hole 36 and is held in place by a clip 44. The clip 44 is fastened to an inner surface of the first endcap 12 by screws 46.
Threadedly mounted on the threaded rod 38 is a clevis 48. FIG. 3 illustrates a sideview of the clevis 48 including a tapped hole 50 in the center thereof. The tapped hole 50 receives the threaded rod 38, as shown in FIG. 2. At a first end of the clevis 48 is a pair of fastening members 52, 54 to which are fastened one end of the gas spring 28. A second end 56 of the clevis 48 is configured to slideably engage a track 58 which is integrally molded in the first endcap 12 (see FIG. 2). The second end 42 of the threaded rod 38 is configured to be engaged by a hex-shaped key, which is inserted through the hole 36 when the second end 42 is properly aligned with the hole 36. The hex-shaped key is employed so as to rotate the threaded rod 38 along its axis of rotation. When the threaded rod 38 is rotated along its axis of rotation, the clevis 48 moves along the length of the threaded rod 38 in a direction that corresponds to the direction which the hex-shaped key is turned. This movement of the clevis 48 permits the gas spring 28 to be adjusted.
FIGS. 4(a) and 4(b) illustrate the upper channel 14, which comprises channel bottom 60 from which extend two channel sidewalls 62. Channel bottom 60 and sidewalls 62 are typically stamped from 13 gauge steel sheet in order to give the upper channel 14 a desired degree of structural rigidity. At each of the ends of the channel bottom 60, a semi-circular region 64 of the sidewalls 62 is cut out to accommodate cold-rolled steel rollers 66, which have a hole 68 therethrough for receiving the pins 24. The rollers 66 are rigidly attached to the upper channel 14 by MIG welding along the edge of the semi-circular cut out region 64 and along the ends of the channel bottom 60. Alternatively, the rollers 66 are integrally cast with the exterior of the upper channel 14 during fabrication.
Additionally, the upper channel 14 comprises stiffener 70, which is welded to an inner surface of the channel bottom 60. Besides providing additional structural rigidity to the upper channel 14, the stiffener 70 has a hole disposed at one end with a threaded ball stud 72 placed within the hole and fixed in place by a nut 74. The ball stud 72 is configured and sized to receive one end of the gas spring 28. The longitudinal centerline 76 of the upper channel 14 is illustrated in FIG. 4(b). FIGS. 4(c) and 4(d) illustrate an alternative upper channel 14′. The upper channel 14′ is constructed to optionally include internal reinforcements. This is particularly advantageous when mounting heavy electronic devices to the extension arm, for example, large computer monitors of the CRT type. Internal within the upper channel 14′ is a rib assembly including a plurality of cross-ribs 400 and angularly disposed secondary ribs 402. By way of example, the cross-ribs 400 are disposed transverse to the sidewalls 62, while the secondary ribs 402 are disposed at an angle so as to form a triangular internal support structure. The cross-ribs 400 and secondary ribs 402 may be formed as an integral member which can be inserted into the upper channel 14′. Preferably, the cross-ribs 400 and secondary ribs 402 are integrally cast during formation of the upper channel 14′.
FIGS. 5(a) and 5(b) illustrate the lower channel 16, which comprises a channel bottom 78 from which extend two channel sidewalls 80. As with the upper channel 14, the channel bottom 78 and sidewalls 80 are typically stamped from 13 gauge steel sheet, which is relatively heavy in order to give the lower channel 16 a desired degree of structural rigidity. At opposite ends of the channel bottom 78, a semi-circular region 82 of the sidewalls 80 is cut out to accommodate cold-rolled steel rollers 84, which have a hole 86 therethrough for receiving the pins 24. The rollers 84 are rigidly attached to the lower channel 16 by MIG welding along the edge of the semi-circular cut out region 82 and along the ends of the channel bottom 78. Alternatively, the rollers 84 are integrally cast with the exterior of the lower channel 16 during fabrication. The longitudinal centerline 88 of the lower channel 16 is illustrated on FIG. 5(b).
FIG. 6 illustrates the second endcap 18. Unlike the first endcap 12, the second endcap 18 does not have a clevis assembly for attachment to the gas spring 28. The second endcap 18 has an endcap shaft 22 for receiving the forearm extension 20, as illustrated in FIG. 1.
FIG. 7A illustrates the forearm extension 20 having a central arm 89 and first and second ends 91, 95, respectively, attached to the central arm 89. The first end 91 includes an opening 93 for connection with the endcap shaft 22 of the second endcap 18. The forearm extension 20 has a second end 95 with the opening 26 for receiving the shaft 90 of the device mount. An opening 97 is provided for access to the interior 92. As seen in FIG. 7B, there is access to the opening 93 of the first end 91 via region 99, which allows the cable 94 to be hidden from view.
Known extension arms, such as those in FIGS. 1-7, may operate satisfactorily, but may not be well suited for low-cost mass production. For example, the rollers 66 and 84, which are attached to the upper and lower channels 14 and 16, respectively, are either welded or are cast to the exterior of the channels. Welding is costly, time consuming, and typically results in an unpleasing appearance. Casting the roller 66 and/or 84 may result in undesirable parting lines, e.g., marks left on a die casting where the die halves meet, which may be visible to customers or end users. Grinding or sanding can remove parting lines. However, this requires additional time and effort during manufacturing, not to mention the associated cost involved.
Because the upper channel 14 may bear the majority of the weight of the electronic device supported by the extension arm 10, it requires a certain amount of structural support, whether from high grade materials or from the supports discussed above with respect to FIGS. 4(a)-(d) and FIGS. 18(a)-(b) of U.S. Pat. No. 6,609,691. High-grade materials can drive up the cost of the device. Additions like the stiffener 70 or the ribs 400 and 402 take up space in the upper channel 14 or 14′, and can limit the range of motion of the gas spring 28. This, in turn, limits the range of motion for the extension arm. While it may be possible to lengthen the extension arm, particularly the upper and lower channels 14, 16, the additional size increases cost and may not be practical for small spaces such as a cubicle or shared office.
Thus, there is a need for extension arms that can be fabricated without time consuming and costly manufacturing steps such as welding, grinding or sanding. There is also a need for extension arms having enhanced structural support without impacting size, range of motion or cost.